This invention relates to a method of generating and processing audio/video broadcast signals in a subscription communication system of the type disclosed in my prior copending application, Ser. No. 383,604, filed June 1, 1982, now pending with respect to which the present invention is a continuation-in-part.
According to the disclosure in my prior copending application, a subscription service station has a program library formed by a plurality of recorded audio/video signal sources from which selected program material is broadcast through signal carrier cable or the like to subscriber stations in response to dialing code selection signals transmitted by standard telephone communication. Transmission from a selected recorded program source in the library is delayed to establish a preceding message period during which program identification and other information is broadcast to the subscriber station.
Various multiplexing methods were contemplated in connection with the foregoing communication system for servicing a sufficient number of subscriber stations to make the system economically feasible. It is however an important object of the present invention to provide a method of processing the program signals in such as manner as to further increase the number of subscribers capable of being serviced and to permit enlargement of the program content of the library from which selections may be made.
Other objects consistent with the foregoing object are to enhance security against unauthorized use of the subscription communication system without drastic modification of the standard television receiver at the subscriber stations.